I've always used o-ring chains. Properly maintained, it should last a really long time on the XT. 17hp just isn't that hard on a chain. laugh

My recall is what Muniac says... 10W is stock, some folks use 15W to firm it up just a touch.

This shall pass, be still and know.
2006 XT225, UNI filter, ProTaper bars, MSR handguards, SS front brake line, Shinko 241's.